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Keeping lead-acid batteries in good condition.

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  • Keeping lead-acid batteries in good condition.

    Can you point me to some good information on maintaining deep-cycle (marine?) and automotive lead acid batteries?

    I'd like some accurate guidelines on charging, discharging, battery chargers, etc.


  • #2
    Here's a couple to get you pun intended.
    Home, down in the valley behind the Red Angus
    Bad Decisions Make Good Stories​

    Location: British Columbia


    • #3
      The key to keeping lead acid batteries good is to keep them charged up fully and keeping the water/acid at the proper level.

      A 12 volt battery that has 12 volts charge in it is considered fully discharged. A discharged battery will develop lead sulphate on the plates and that is what ruins most batteries.

      Battery tender type trickle chargers work well for this. I just picked up a couple of them from Sears for a little over $20 on sale.






      • #4
        Keep them on a float charger.


        • #5
          $20 and one of these does the trick for me:

          The idea is to trickle charge the battery to keep the plates from sulfating which renders the battery useless. I installed one in my backhoe and both of my trucks. Works like a charm
          "To invent you need a good imagination and a pile of junk" Thomas Edison

          Better to have tools you don't need than to need tools you don't have

          73's KB3BFR


          • #6
            Get a float charger that keeps them at 13.6 to 13.8v and no higher (idealy closer to 13.6v), lower is also not very good.

            Leave it on them 24/7.. Or at least connect it for a few days every month if you wanna rotate it between batterys.
            Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.


            • #7
              In addition to what's been said above, don't allow the batteries to set directly on a concrete floor, put a piece of wood under them if you do.
              Something about it seems to encourage discharge. (temperature differential?)
              I cut it twice, and it's still too short!


              • #8
                Continuous "dumb" float (the old way, but still around) isn't great for batteries either. "Marine" chargers are often 3 or 4 stage - they monitor the state of the battery and adjust the charge conditions to suit. One of my chargers will also pulse charge a zero volt battery - I've bought a few back from deader then dead!

                I put quality multistage chargers on all my intermittent use devices - mower, generator, etc... I'm now into year 8 on all batteries. Prior , I was lucky to get 2-3 years. Oh... these are cheap UI size lawn tractor batteries that only have a 6 month or one year warranty. Neighbor now has the same chargers on all his collector cars.

                This is the charger I buy :

                here's an extract from the blurb :

                Multi Stage charging cycle

                Stage 1: Deep Discharge Charging Pulse Mode
                The Charger starts charging at 0.5V and give pulse current up to 5V. This has effect of removing loose sulphation formed during deep discharge state of the battery.

                Stage 2: Constant Current Mode (CC)
                The charger changes to constant current 3A. When the battery voltage reaches to 14.4V, the charging stage changes from (CC) Constant Current to CV (Constant Voltage) mode.

                Stage 3: Constant Voltage Mode (CV)
                The charger holds the battery at 14.4V and the current slowly reduces. When the current reaches at 0.5 C (C= Battery Capacity), this point called the Switching Point. The Switching Point is one of the great features of this battery charger that it can adjust the current automatically according to the battery capacity. Other chargers without microprocessors are not capable to adjust the current automatically.

                Stage 4: Standby Voltage Mode
                The charger maintains the battery voltage at 13.8V and current slowly reduces to zero. Charger can be left connected indefinitely without harming the battery.

                If the battery voltage drops to 12.5V, the charger changes from any mode to Constant Current mode and restart charging. The charging cycle will go through Stage 2 to Stage 4.
                Last edited by lakeside53; 10-04-2011, 11:52 AM.


                • #9
                  Sir batteries can be fickle things and if you have mixed types you need a special charger.A standard car battery vs a trolling motor battery vs a gelled electrolyte cell charge at different rates(c rates varies with amperage) I use an Exide fully automatic charger that will charge most every thing and has a trickle charger built in they are not cheep.
                  A gentlemen above mentioned lead sulphate and he is correct the sulfate may be driven back into solution by temporarily over charging the cell, older service station models are able to do this the over charge is not much and the battery's temp must be monitored.If you have a Ham Radio friend the handbook goes into great detail on battery's in general and how to drive the sulfate back into the solution.Battery's can explode so be very careful.
                  I never trust a fighting man who doesn't smoke or drink.
                  William Halsey

                  As a Machinist & Gunsmith I like to hear how to not can't do. P.A.R.


                  • #10
                    Every single time you discharge a Lead Acid battery (of any type, wet, gel, or AGM) you are forming Lead Sulphate. That's just how the chemistry works.

                    If you leave a battery sitting around at a partial state of charge, then some of tha Lead sulphate is disolving and re-crystalising. This leads to the growth of large Sulphate crystals that are hard to persuade back into solution under charge. I've heard the terms soft sulphation and hard sulphation used to distinguish between the two.

                    If a battery that was otherwise in very good condition has been left discharged for a while and has hard sulphated and won't take a charge, then I've had some good results from and electronic de-sulphater/battery rejuvinator. They usually spout some rot about hitting the resonant frequency of the sulphate bonds, but certainly the fast rise pulse (they're just a simple flyback psu with no feedback) does seem to work.

                    A special case can occour with an AGM type battery. Lead Sulphate is an insulator and you can almost completely coat the very thin plates used in AGM batteries if you overdischarge or leave a heavily discharged AGM battery sitting. This can make them almost impossible to recharge with an ordinary charger. I've had to use around 60 volt on a 12 volt AGM to get it to pull any current. With a good bench supply, I can just set the current to say 100mA and leave it to recover. The de-sulphators seem to do the job a little faster.

                    The advice about not leaving batteries on a concrete floor is mostly true for the old rubber cased types. They would loose charge. Modern batteries will loose capacity simply by being cold, which is more likely if they're sitting on a concrete floor.
                    Paul Compton


                    • #11
                      I bought a Yuasa battery maintenance charger some years ago and leave it connected to my generator's battery all the time. Aside from ensuring the generator will start when needed, it keeps the battery in good shape. It wasn't particularly expensive.
                      Try to make a living, not a killing. -- Utah Phillips
                      Don't believe everything you know. -- Bumper sticker
                      Everybody is ignorant, only on different subjects. -- Will Rogers
                      There are lots of people who mistake their imagination for their memory. - Josh Billings
                      Law of Logical Argument - Anything is possible if you don't know what you are talking about.
                      Don't own anything you have to feed or paint. - Hood River Blackie


                      • #12
                        As for the comment about a "dumb" float.....

                        There is NO SUCH THING AS A FLOAT CHARGER

                        "Floating" the battery means matching its EMF with the external supply (following temp changes) so that there is NO charging going on....

                        When the load exceeds the external supply capability, the battery supplies current. THEN it gets recharged when the draw goes below the external supply capability.

                        batteries in that condition (railroad signal used to be like that, also phone company batteries, etc) will last a LONG time.

                        The other folks are correct.... sulphate is created in discharging the cell, and you need to recharge soon.

                        The pulse "reforming" chargers probably work by putting a high enough pulse current in that the "disconnected" sulphate is converted by the field in the water.

                        Keep eye on ball.
                        Hashim Khan


                        • #13
                          Hmmm... semantics .. there is... dumb chargers that have no smart precision regulation (little more then a bridge rectifier and a tranfomer) which tries to float by approximating the transfomer voltage to the battery requirements... and often allow the voltage to rise too high too high and "over-charge" by definition... They are still sold and yes, are misleading to Joe consumer. Mabye a better name is dumb charger.

                          Over-charging is bad for battery longevity. The marine guys figured this out 20 years ago, Telco - 75 years ago.
                          Last edited by lakeside53; 10-04-2011, 10:18 PM.


                          • #14
                            Originally posted by Scottike
                            In addition to what's been said above, don't allow the batteries to set directly on a concrete floor, put a piece of wood under them if you do.
                            Something about it seems to encourage discharge. (temperature differential?)
                            I this crap is the best you have to offer, you should keep it to yourself. The OP did not ask for old wives tales and BS.


                            • #15
                              There is no "float charger" because either the battery is being "floated", OR it is being charged, and the two are not one thing.

                              That said, you can "charge" a battery at a low rate about forever, and it will come to no harm..... The "low" rate being C/50 or less..... so 2 amperes max for a 100 ampere hour battery. Less being better.

                              No doubt a chorus will say "no way", but I have had batteries being charged at a similar low rate for almost 20 years..... they last about 12 years for me that way. They are in a solar power setup in the shed. The lowest charge rate is about 2 or 3 A, and there are 400 AH of batteries, so about C/100.

                              Keep eye on ball.
                              Hashim Khan